JavaScript What is wrong with my method for predicting the election?

Given the fact that there are 51 states and districts, there are 251 subcollections of the 51 states, which I can't possibly iterate over entirely. So what I do is find 210 subcollections of states whose electoral votes summed are 270 or greater. I then sum together the probabilities of Trump winning each of those 210 collection of states. Finally, I multiply that sum by 241.

Anything wrong with that? Because I'm getting a results that seems wrong.